fix: remove redundant rollback, document asymmetry in cancellation notifications

backend/handlers/payments/handlers.go

@@ -1802,7 +1802,6 @@ func CreateTipPayment(w http.ResponseWriter, r *http.Request) {
 
 	paymentID, err := service.CreatePaymentRecordTx(r.Context(), tx, record, nil)
 	if err != nil {
-		_ = tx.Rollback(r.Context())
 		log.Printf("Failed to create payment record: %v", err)
 		http.Error(w, "internal server error", http.StatusInternalServerError)
 		return

backend/handlers/payments/payments_test.go

@@ -1019,11 +1019,6 @@ func TestCreateBookingPayment_MultiplePartialAllowed(t *testing.T) {
 	}
 }
 
-func TestSquareWebhook_DevMode_NoSignature(t *testing.T) {
-	t.Parallel()
-	t.Skip("webhook handler tested in webhooks package")
-}
-
 // ============================================================
 // User Booking Payment Tests — deposit, full, partial, balance
 // ============================================================